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111.
112.
This paper discusses formulation of the total problem of flow of an incompressible liquid over a body, with formation of a closed stationary separation zone as Re . The scheme used is based on the method of matched asymptotic expansions [1]. Following [1], it is postulated that the separated zone is developed (i.e., it is not infinitely fragmented and does not vanish as Re ), and the flow inside it has a definite degree of regularity with respect to Re. With these hypotheses we can use the Prandtl-Batchelor theorem [2], which states that, in the limit as Re , a region of circulating flow becomes vortex flow of an inviscid liquid with constant vorticity . Therefore, a basis for constructing matched asymptotic expansions is the vortex-potential problem (the problem of determining a stream function , satisfying the equation = 0 in the region of translational motion and the equation = in a certain region, unknowna priori, of circulating motion). In the general case the solution of the vortex-potential problem depends on two parameters: the total pressure po and the vorticity in the separated zone. These parameters appear in the condition for matching the solutions of the first and second boundary-layer approximations (at the boundary of the separated zone for the end Re values) with the corresponding solutions for the inviscid flow. It is shown in the present paper that the conditions for matching the cyclic boundary layer with the external translational flow are the same additional relations which allow us to close the total problem. Thus, in using the method of matched asymptotic expansions to solve the problem of flow over a body with closed stationary separation zones one must simultaneously consider no less than two approximations.Translated from Izvestiya Akademii Nauk SSSR, Mekhanika Zhidkosti i Gaza, No. 2, pp. 28–37, March–April, 1978.The authors thank G. Yu. Stepanov for discussion of the paper and valuable comments. 相似文献
113.
Maksim A. Kolosov Elena H. Shvets Dmitriy A. Manuenkov Sergey A. Vlasenko Irina V. Omelchenko Svetlana V. Shishkina Valeriy D. Orlov 《Tetrahedron letters》2017,58(12):1207-1210
6-Unsubstituted 7-R-4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidines (R = H or Me) were synthesized via two pathways: (a) deacylation of the corresponding 5-acetyl Biginelli-like precursors in KOH/H2O and (b) reduction of the corresponding 1,2,4-triazolo[1,5-a]pyrimidines using LiAlH4. The products could be easily formylated at position 6, which is promising for the further synthesis of functionalized 6-substituted derivatives of 4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidines. In contrast, 6-acetyl-7-(4-(N,N-dimethylaminophenyl))-5-methyl-4,7-dihydro-1,2,4-triazolo[1,5-a]pyrimidine undergoes a cascade process in KOH/H2O, leading to the formation of a 4,5,8,9-tetrahydro[1,2,4]triazolo[5,1-b]quinazoline derivative. 相似文献
114.
F. Binon A. M. Blick S. V. Donskov S. Inaba V. N. Kolosov V. M. Kut’in M. E. Ladygin A. A. Lednev V. A. Lishin Yu. V. Mikhailov J. P. Peigneux V. A. Polyakov V. D. Samoylenko A. E. Sobol J. P. Stroot V. P. Sugonyaev K. Takamatsu T. Tsuru Y. Fujii G. V. Khaustov 《Physics of Atomic Nuclei》2007,70(10):1713-1716
The reaction K ? p → ηη(Λ/Σ0) at a momentum of 32.5 GeV/c was studied for the first time. The experiment was performed by using the GAMS-4π spectrometer at the 70-GeV accelerator of the Institute for High Energy Physics (IHEP, Protvino). The f 2(1525) resonance was observed in the effective-mass spectrum of the ηη system at a low background level. The cross section for f 2(1525) production was measured. The branching ratio for f 2(1525)-meson decay to ηη and K $\bar K$ was found to be R = 0.119 ± 0.015(stat.) ± 0.036(syst.), which is in agreement with the world-average value. 相似文献
115.
Russian Physics Journal - General patterns of localized plastic flow development are described at linear work hardening stages of nineteen metals. Correlations between the position of the element... 相似文献
116.
S. A. Kurkin A. A. Koronovskii A. E. Khramov A. A. Kuraev S. V. Kolosov 《Technical Physics》2013,58(10):1489-1497
A two-dimensional numerical model is used to study the generation of powerful microwave radiation in a vircator with an inhomogeneous magnetic field applied to focus a beam. The characteristics of the external inhomogeneous magnetic field are found to strongly affect the vircator generation characteristics. Mathematical optimization is used to search for the optimum parameters of the magnetic periodic focusing system of the oscillator in order to achieve the maximum power of the output microwave radiation. The dependences of the output vircator power on the characteristics of the external inhomogeneous magnetic field are studied near the optimum control parameters. The physical processes that occur in optimized virtual cathode oscillators are investigated. 相似文献
117.
S. M. Masloboeva V. N. Kolosov V. M. Orlov T. Yu. Prokhorova M. N. Miroshnichenko 《Russian Journal of Applied Chemistry》2012,85(7):1025-1028
Effect of various extractive systems (triisoamyl phosphate/HF+H2SO4, n-octanol/HF+H2SO4, n-octanol/HF+HNO3) used to obtain potassium heptafluorotantalate from plumbomicrolite-based raw materials on the purity and characteristics of sodium-reduced tantalum powders was studied. Application of the extractive systems provides production of high-purity potassium heptafluorotantalate from raw materials based on products formed in processing of the plumbomicrolite concentrate. 相似文献
118.
119.
We have performed exact numerical calculations for a hydrogen atom perturbed by a uniform electric field for some Stark sublevels with n = 12, 13, 14, 15. The results are compared with recent experimental data for excited states of sodium. 相似文献
120.
Starodub T. N. Kolosov M. A. Fenske D. Fuhr O. Shishkina S. V. Piotrowska W. 《Crystallography Reports》2022,67(2):188-192
Crystallography Reports - An anion radical salt of 7,7,8,8-tetracyanoquinodimethane (TCNQ) with the complex composition (N–Me–DABCO)(TCNQ)2 (1) has been synthesized. The crystal... 相似文献